Today, black powder is still a useful propellant for specialized purposes. For example, black powder is somewhat easier to ignite than modern propellants; it is commonly used as a booster charge in large-caliber military applications. In spite of the ability of black powder to allow the use of lethal force at a distance, it was not without problems.
- Black powder has a limited amount of total energy per unit of volume. To gain greater velocity, a larger volume of propellant must be used, necessitating a larger cartridge case. With the trend to repeating firearms, large cartridges common to single-shot black powder firearms could not be accommodated.
- In cartridge firearms, velocities seldom exceed 1400 ft/sec.
(426 m/sec). This again is a limitation of energy content and cartridge size.
- Black powder is volumetrically inefficient. Depending on the grade, granulation, and loading density, gas production is only 45 to 55 percent of the total output. The remaining inert solids, largely dense smoke and fouling, contribute nothing to propulsion.
- Black powder produces a dense smoke cloud. As military tactics shifted from massed troops to individual riflemen, a smoke puff helped the enemy to spot the shooter’s position.
- Black powder residue is corrosive to steel. Several by-products of black powder combustion are hygroscopic, releasing corrosive compounds when hydrolyzed. This accelerates wear to the firearm.
The goal of researchers became the development of propellants that overcame these shortcomings.
Replica Black Powders
Pyrodex® (Reg TM of Hodgdon Powder Company) is a late twentieth century development that is today classed as a replica black powder. It was developed to overcome the high transportation costs and storage limitations of black powder. For such purposes, it falls in the same shipping class as modern propellants.
Pyrodex is formulated to replace black powder on a volume—not weight—basis. In keeping with its replica duties, added materials generate the satisfying puff of white smoke so characteristic of original black powder.